Diretta, the new digital egg of Columbus? (Eng)

Sometimes things can turn out strange. Something I’m not at all involved with, also hardly or not interested in appears on my doorstep. What should I do with it? So it was a little bit like that with the introduction to the adventure below. I asked for a power supply to see if a DAC I was working on at the time could be made more lively. But was at the same time unrequested and unintentionally pulled into a new brand-new audio adventure. The beginning of code name: Diretta. And what an adventure it turned out to be!

Boxing Day…

A few months back I asked the Dutch importer Audiotweaks for a Ferrum Hypsos power supply. ‘I have to be in the area anyway,’ wrote Piet de Vries, ‘I’ll drop it by.’ To be honest, I was shocked when, two days later, Piet took not only the box with the requested power supply but also several boxes of other equipment out of his delivery van. Piet, what is this? ‘You should try this too, I think you will like it’. To be honest, I didn’t feel like it at all. Still very busy testing a few other audio devices, which would require, among other things, the aforementioned Hypsos power supply. ‘Piet, I’m really not going to completely overhaul things in my audio rack right now, I’m busy doing other kinds of things and don’t want to change the periphery around it’. ‘If you have some time to spare, go ahead and take it easy,’ Piet told me during a cup of coffee.


In addition, I was still fully enjoying a newly built BerryStreamer XL Ultimo, with all the bells, whistles and clocks in it that took the device from extraordinarily good to almost unbelievably good. So the urge to convert all this to a different setup was, to put it mildly, not overwhelming.

What’s inside the boxes?

In Piet’s cartons are an audio server from Pachanko, with external power supply, a DAC from SPEC, again with external power supply, a so-called Diretta Bridge from SPEC and a separate Diretta Lucia Picolo module built by Piet himself in a bamboo wood box. And precisely this somewhat unsightly little box is going to play a very important role in this adventure….

SPEC RMP-UB1 Diretta Bridge

Since it’s all new to me, it’s kind of practical to have a temporary setup, just to make sure everything works here.We hooked things up and started up everything. Chan from Pachanko was texted to remotely change some settings in the server. And a short while later the music was playing. Piet went home and I was left with a complete equipment set up in front of my audio rack and a pile of empty cartons….

But first: what is Diretta?

Yes, so what is Diretta anyway? Diretta is the brainchild of Japanese artist Yu Harada. And no, it is not yet another digital audio format like WAV, FLAC, ALAC, DSD, MQA … or you name it. Since it’s also brand new to me and so there is much I don’t yet know about the ins and outs of the processing concept, I will let Yu Harata/ Oliospec/SPEC do the ’talking’ here.

What is Diretta?

Diretta is a completely new protocol designed for high-end audio. In a digital audio player, there are many factors that can affect the sound quality. With the transmission of the digital packets, there is also noise generated in the power supply that can greatly affect the final sound quality. To suppress it, a low-pass filter is usually used, with coils and capacitors. The low-pass filter reduces the peak-like noise characteristic of digital signals. But as you may know, a low-pass filter affects only the higher frequencies but allows the fluctuations in the low frequencies to pass through unhindered. Since this is not noise, there is no need to remove it. After all, we don’t see noise.However, if we look at the current, we see that there is noise that does affect the audible bandwidth for a period of time. It is difficult to remove this noise electrically. At Diretta, we figured that if we could suppress this noise, the sound quality could be significantly improved! However, it is very difficult and impractical to configure all CPUs and other components with a constant current like, for example, a Class A amplifier.

However, if we could solve this problem with a software approach, a realistic implementation would be possible.There is a way to be able to do this. That is to average the data processing and thus reduce power fluctuations.The Diretta Host operates synchronously with the Target. The Target receives data packets from the Host. Processes them and then sends them out to the DAC at regular short intervals.

Getting Started

We connect the Pachanko Constellation Mini SE server with the SPEC RMP-UB1 Diretta Bridge. The Pachanko server is powered up. Roon is signed in to the Roon server on the Pachanto in the Roon app on the iPad. Everything is instantly recognized in the Roon Settings/ Audio menu on the iPad. And Diretta will be chosen as the Roon player. However, the only thing missing on my BerryStreamer Ultimo is a USB connection.The nice thing is that there also has been an RME ADI-2 DAC in my audio rack since a week. A DAC that boasts a multitude of connection and setup options. This DAC is sounding pretty good. The sound I listen to is clean, but also somewhat uninspiring. I will not mention the word “digital,” but I am hard-pressed not to… Just to figure out if there is some juice to breathe into the RME DAC with a better power supply, I asked for the Ferrum Hypsos power supply.

Before and after…

For proper comparisons, the DAC is first connected to the the server the regular way. With a the USB cable plugged in straight in between the Pachanto server and the RME DAC. This changes little to nothing in my opinion above. I frankly notice little to no differences from the second server in in the audio rack, the Silent Angel Rhein. Both can be quickly switched over. Then the RME is connected via the SPEC Diretta Bridge …

What is happening here? How is this possible? The RME DAC suddenly gets more space, more depth, more focus after the switchover… But the other thing that stands out is the low end. That is deeper and more tight. If this is a prelude to the things to come? That promises to be something!


The SPEC DAC combination reveals exactly the same kind of sounds. Definitely a fine DAC, but again not very special to my ears when connected straight to the Pachanto server by USB. When plugged into the SPEC Diretta bridge, the same DAC, however, is that much nicer… I have switched back a few more times, without a chance! Tasted it once and you’ve lost!


As it happens, the DDDAC1794 on a shelf has just this week been upgraded with an … indeed, USB connection. So this apparently simple board is soon about to join the Diretta adventures. This DAC too, plugged into the SPEC RMP-UB1 Diretta bridge does sound that much better…. Simply stunning how good this very basic DDDAC1794 NOS DAC is sounding here.

I subsequently listened to this non-stop for one week. With no further changes to anything. After a few hours of listening, I do not even remember that I am sitting here listening to the most basic version of the DDDAC1794. I have been listening silently to music and nothing else! And do not even feel the urge to change things any more soon.

De Diretta Method

So is this the kind of thing the Diretta method does? In the meantime, my initially reluctance has given way to unbridled enthusiasm about Diretta! That has not diminished until today. Already one thing is certain: Diretta is not about to leave this house!

The financial aspect

If you’re in the happy circumstance that the budget isn’t an obstacle financially and want to have a plug ‘n’ play no fuss solution for your server, with all of the options already pre-installed for running Diretta? Then you can purchase, for example, a SPEC RMP-UB1 Diretta bridge and one of the ready-to-use fine Pachanto audio servers.

Pachanto SE mini audioserver

With the last one, you instantly get outstanding ‘remote’ manufacturer support, in case something still goes not exactly right. One app to Chan from Pachanto and the issue is quickly solved via ‘Anydesk‘.During the weeks the Pachanto SE Mini server has been here in the rack, I haven’t once experienced an issue. Practically foolproof, therefore. It’s just a simple press of the start button and the music is playing within a minute. There’s just one drawback… The set-up that we enjoy very much listening here, Pachanto server + power supply + SPEC bridge is chopping firmly into the hobby budget.

Diretta for ordinary mortals

Nothing goes for nothing (yet), but personally I think Diretta shouldn’t only be achievable for the wealthier among us. The average music lover without an infinite large budget has to be in a position to save up for it as well. The latter was no easy task, but it worked out! You have to put some effort into it, but I assure you that it will be well worth each euro and each minute that you put into it!

So what do we need?

As I wrote, Diretta a new data transmission protocol between the (audio) server and DAC which optimizes the digital data flow. Thus, what we need is a Diretta Host as well as a Diretta Target. One doesn’t do anything without the other.The Host, in this case, is a PC running under Windows 10 Pro set up specifically to be an audio server. Ideally, it would be a PC with dual LAN ports. Then you can make a short link with the Diretta Target. But without hesitation, also a PC with a single LAN connection could be used. In this case, both the Host PC and the Target will be connected to network switch.

De Oliospec Canarino DUB connected to the second LAN-poort on the audioserver.

De Oliospec Canarino DUB and the audioserver connected with a netwerkswitch


As with the majority of readers here, does budget need to be a consideration? If so, you might also consider using a (used) i3 or i5 Intel NUC with fresh installed Windows W10. As lightly installed as possible. Or, without any unnecessary software that is not needed at all for streaming audio. Best of all, a streamer can be used ‘headless’ so the keyboard, mouse and display need only be used during the initial setup. With the fine software from Fidelizer running on it that keeps all unnecessary processes not related to audio streaming at a minimum.

Diretta ASIO driver

Installed on the Host is the Diretta ASIO driver which can be downloaded from Diretta’s site.

Building instructions?

While I write very coolly here about building an audio server myself, if it is the most common thing in the world, I should quickly add that until a few months ago I had never built a PC from scratch. My experiences with doing anything to a PC myself were limited to installing SSD storage and adding extra RAM memory. Or installing Roon Rock on an Intel NUC. I am a PC user, and thus anything but an IT specialist. That makes me extra proud that my audio server turned out so well. It plays beautifully, very fast and very stable. In addition, the server is energy-efficient and thus has low heat generation while playing music.But keep in mind: building a PC yourself, however, is no Rocket Science. If I can do it, with help from Google, YouTube and some co-hosting by my brother, a lot of hobbyists can do it…Am I going to write a self-build project about this? No, that’s not going to happen. I see this audio server, and Marco’s, purely as a successful hobby project that we keep to ourselves. There are also no plans to build more than these two.

If you know absolutely nothing about PCs, prefer not to have anything to do with these things, let alone building an audio server yourself (argggg), simply look at a plug ‘n’ play Pachanto server.

Some explanation

What I do want to tell you is that my DIY audioserver use a motherboard with dual LAN ports, an Intel i5 processor, a Samsung 500 GB SSD slice on which the Windows 10 pro software, the Roon server, the Diretta ASIO driver and Fidelizer installed. Also, 16 GB of DDR4 RAM and a very sturdy linear power supply. All built into a nice passively cooled case from Streacom. How to make the server ‘headless’ can be found at the Roonlabs site, among others.

The Diretta Bridge

This is the most important part of using Diretta. The Host PC/ Streamer is connected to the Diretta Bridge via a LAN cable. Which in turn is connected to the DAC via a USB cable.

Diretta Lucia Piccolo

Lucia Piccolo bridge modules are supplied by Diretta to manufacturers and can be configured as preferred. A Diretta application can also be implemented by the manufacturer directly in the DAC, as Sforzato was the first to do. Which is hardly surprising, the developer of the Diretta protocol, Yu Harada, was formerly an employee of Sforzato. SPEC was also an early participant in the Diretta system and uses a custom tweaked Lucia Piccolo module in the already mentioned RMP-UB1.

A second PC

An alternative method of creating a Diretta target is with a second PC. Into this is inserted a USB stick with the necessary software that creates a Diretta Bridge when the PC is booted. It is also possible to configure a Diretta Bridge with a Raspberry Pi in the same way. I must say that both of these methods have little appeal to me. Using an additional PC given the space it takes up and the unnecessary power consumption. A growing concern anno 2022….The Raspberry Pi seems interesting, but in my opinion it is neither. This is because the I2S outputs cannot be used.Even when using a Raspberry Pi, the USB output is a necessity. And isn’t it the USB connections on the Raspberry Pi that have a dubious audio reputation? Don’t forget that the Diretta bridge software needed here on the USB stick also costs 300 euros. The necessary software on the USB stick can also be downloaded from the Diretta site in a ‘try before you buy‘ version for the PC/ Raspberry Pi. This works is limited to half an hour, after which the Target must be rebooted.

Much better!

It’s pretty clear to me. A Bridge based on a Diretta Lucia Piccolo is the most ideal option. A nice piece of technology, super fast startup and very economical in terms of energy consumption. In the past, Piet got a loose Lucia Piccolo brigde from Yu Harada and built it into a simple wooden cabinet.I connected that box as well. Powered by the, yep, there it is again, the superdeluxe ‘Swiss army knife’ among audio power supplies, the Ferrum Hypsos. This is where I wanted to build on. But that caused too many struggles and costs. Loose Lucia Piccolo modules can only be bought by companies and in large quantities. But we have found a wonderful solution!

Oliospec Canarino DUB

Oliospec Canarino DUB

Then we discover a beautiful device from Oliospec. The Canarino DUB. Based on, yes, the Diretta Lucia Piccolo electronics! Oliospec is a Japanese company that builds the Diretta module with all its options in a nice rock-solid compact metal case. Unfortunately, Oliospec is totally focused on the Asian countries around Japan. The site is only in Japanese. But to our surprise (Piet de Vries and me): the Oliospec Canarino bridges can just be delivered to companies via Diretta itself. After some correspondence back and forth with Yu, the Oliospec Diretta bridges can be delivered. Audiotweaks thus becomes the official importer for the Netherlands, Benelux and Germany. And of course, the Oliospec Bridges are also for sale in our shop.The Oliospec DUB ASIO driver can be found here.

Oliospec Canarino DUB back


Why has so much energy been put into yet another digital egg of Columbus in audio streaming? I can be brief about that. Although initially perhaps not so interested in all the stuff Piet brought me to play with, after all I was really extremely satisfied with my audio streaming quality at the time, the whole situation was reversed 180 degrees and my enthusiasm had no limits from then on. Something has to be done with this! I want to do something with this!

Reading in…

From then on I started collecting all the information I could find about the Diretta protocol and started reading up on it. And I am still not finished with that. The exact operation of the Diretta Protocol is still not entirely clear to me. And Yu Harada, the creator of Diretta, may be a star in his field, but he has considerably less knowledge about promoting his beautiful invention. Initially, I have to work with the not always clear information that Yu sends me from Japan. I was regularly “Lost in Translation,” like Bill Murray in the movie of the same title.Some German and one French publications, however, have been very helpful in helping me understand Diretta a little better. Slowly but surely we come to want to be his….

Oliospec Canarino DUB inside

Another new format?…pfff….

Absolutely not! Let it be clear that Diretta is not yet another playback format. Which we already have far too many of. No, Diretta doesn’t even have anything to do with formats. Diretta works with any Windows-based audio server. And every DAC I connect to a Diretta Bridge is immediately recognized. And the results are amazing every time.

Fiddling on the margins

In the past I have spent quite a lot of money on all kinds of ‘USB polish’. Fortunately, I was able to get rid of most of it, but here and there I still find some in the junk box. All in all, I dare say I even spent significantly more on these props than what the Oliospec Canarino DUB with a nice power supply costs. Compared to how big the gain with playing with a Diretta Bridge is between audio server and USB DAC, I dare to safely label all my purchased USB “improvements” from the gray past as fiddling at the margins. One magic stick or box might do a little more than the other, but at some point I was done with the USB connection between my server and DAC. And I successfully moved on to pure network streaming. Until now, several years later… How things can change….


The Diretta protocol allows good USB DACs to perform better than ever. Better than I ever expected even in my wildest dreams. My favorite DAC, which I normally enjoy my music on every day and which I thought, “this is the limit, better than this I can hardly imagine,” also performs better! For me, Diretta is the most stunning audio discovery of 2022!In the next episode, we dive a little deeper into the installation of Diretta and my own BerryStreamer gets connected to the Diretta Protocol.

Dick van de Merwe

Dick van de Merwe is een echte buizenveteraan. Zijn Triodedick zelfbouw projecten worden wereldwijd door hobbyisten gebouwd. Reeds vanaf 1997 deelt hij zijn kennis via geschreven en on-line media.

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